Medial orbitofrontal cortex repetitive transcranial magnetic stimulation may best treat addiction & preserve working memory for the nicotine-dependent

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Tracy Dubin¹ (TDubin@usc.edu), Xingbao Li; ¹Medical University of South Carolina

High-frequency repetitive transcranial magnetic stimulation (HF-rTMS) over the dorsal lateral prefrontal cortex (DLPFC) is the generally accepted neurostimulation protocol for smoking cessation treatment, although medial orbitofrontal cortex (mOFC) placement may better aid in preserving working memory. This exploratory study assessed DLPFC versus mOFC rTMS placement in patients with Tobacco Use Disorder (TUD) to reveal possible memory harms, as tested using the N-back working memory task. The Medical University of South Carolina conducted a double-blind, sham-controlled, randomized clinical trial of participants (n=18, 9 female) aged 49.8 [9.7] (mean [SD]) nearby Charleston, South Carolina, who enrolled for rTMS smoking cessation treatment (15 sessions over 3 weeks). rTMS was sham or active MRI-guided to the DLPFC (10 Hz, 3000 pulses each session) for facilitation protocol or to the mOFC (1 Hz, 900 pulses each session) for inhibition. N-back studies occurred prior to rTMS treatment #1, #6, #11, #15, and 1 month after rTMS #15. 16 participants began treatment: 9 received DLPFC rTMS; 7 received mOFC rTMS. 12 participants (7 DLPFC vs. 5 mOFC) were analyzed. Mixed model results showed significantly different correct trials between 0-back (5.29±0.31), 1-back (3.27±0.31), and 2-back (2.21±0.31), (p < 0.01). A trend difference existed between DLPFC treatment (3.24±0.24) and mOFC treatment (3.93±0.25), (p=0.054), in stimulating working-memory accuracy. Though the DLPFC controls over working memory, the mOFC mediates task retrieval, outcome-specific information, and goal-oriented action. This could account for the trend difference favoring mOFC placement. More research must be done to affirm this is the best placement protocol.

Topic Area: EXECUTIVE PROCESSES: Working memory